Manchester United have said that Ben Foster has been ruled out of England's World Cup double-header against Ukraine and Belarus with a chest injury.

The Football Association did not specify Foster's injury when the squad was released last night, but now United have stated that the 26-year-old is being "investigated" for an injury sustained during Saturday's 2-2 draw with Sunderland, although one not serious enough to prevent him from completing the match.

Conspiracy theorists had suggested an injury was merely the excuse for omitting Foster when the decision had been taken on the grounds of form.

The goalkeeper has been blamed for Sunderland's second goal after being out-muscled for the ball by Kenwyne Jones. This came two weeks after what Sir Alex Ferguson described as a "difficult" afternoon against Manchester City, when Foster was blamed for two goals, losing the ball to Carlos Tevez for Gareth Barry's opener, then going down far too quickly for Craig Bellamy's second equaliser.

Foster's chances at United look like being severely limited after the international break as Edwin van der Sar is due to return after breaking two fingers in a game with Bayern Munich in July.